Amine Functionalized Wheat Bran Husk as Bio-Based Organic Adsorbent for Low-Density Polyethylene Composite of Carbon Dioxide Capture

This study aimed to prepare a bio-based organic adsorbent (W-PEI) with amine functionalization via Schiff’s reaction without carbonization of biomass. The bio-based organic adsorbent was prepared from wheat bran husk (WH), and amine functionalized to absorb CO₂ gas by conjugating polyethyleneimine (PEI) via Schiff’s reaction to the aldehyde groups of periodated WH (p-WH). Then, the bio-based organic adsorbent was compounded with low-density polyethylene (LDPE) using a twin screw extruder. The polymeric composites (LDPE/W-PEI) and W-PEI were studied to characterize chemical structure, thermal properties, and CO₂ adsorption ability. The CO₂ adsorption capacity was measured by thermogravimetric analysis (TGA), and the analysis was performed through the exchange of N₂ and CO₂ under isothermal conditions at 75 °C. The amount of CO₂ adsorption was 0.425 mmol/g of W-PEI powder, while that of polymeric composite (LDPE/W-PEI_20%) containing 20 wt% W-PEI was 0.034 mmol/g, which corresponds to an adsorption efficiency of 40% compared to that of the powder state. Therefore, polymeric composites with improved CO₂ gas adsorption could be successfully applied to food packaging and building materials. [Figure not available: see fulltext.].